1. Field of the Invention
This invention relates to roof ridge ventilators. More particularly, the invention relates to plastic roof ridge ventilators comprised of a one-piece polymeric material having longitudinally oriented vent panels wherein the vent panels comprise alternating slots and slats each having a trapezoidal configuration.
2. Reported Developments
Ventilators for attics of buildings are perforated or baffled vent openings in the underside of the eaves of an overhanging roof or facia and on the roof ridge overlaying the open roof along the length of the roof. The vent openings allow outside air to flow into the attic to equalize the interior attic temperature and pressure with that of the outside environment. This equalization helps to prevent degradation of the roof structure, reduces the accumulation of condensation in the insulating material covering the floor of the attic thereby increasing the efficacy of heating/cooling of the living space in the building covered by the roof structure.
The ventilator system of the prior art is typically comprising: a roof ridge ventilator and a soffit ventilator. The roof ridge ventilator overlays the open roof along the length of the roof for exhausting the air from the space below the roof and the ceiling of the attic, i.e., as the air entering the attic through the soffit vent mixes with the warmer air in the attic, it has to be expelled through an opening in the roof ridge where the lighter, warmer air accumulates. Desirably, the volume of air intake through the soffit ventilator should be balanced by the volume of air exhaust through the roof ridge ventilator. In an optimum soffit ventilator/roof ridge ventilator system there is a balance between the net free open area presented by such system. The terminology "Net Free Open Area" or NFA means the cross-sectional area of a ventilator system which is open for passage of air therethrough. The appropriate balance of the net free open area of a soffit ventilator and roof ridge ventilator is imperative. Thus in many existing and newly built buildings there is a potential for an out of balance soffit/roof ridge ventilation system.
Ventilation systems should also provide against insects entering into the attic space of buildings. While large perforations in the soffit and roof ridge ventilation panels would render the desired flow of air through the attic space, they would also allow ingress to insects therein to form insect colonies.
In addition to having good ventilation of the attic space and preventing ingress of water, snow and insects into the attic space, the desiderata in a ventilation system includes: structural strength and stability to withstand the effects of the elements, such as high wind; strong structural support against collapse or warping, such as occurs by the accumulation of snow or ice or by the weight of the installers accidentally stepping on the roof ridge ventilator; easy handleability on installation; and low costs.
The present invention is directed to roof ridge ventilators which preferably are used in conjunction with an adequate soffit ventilator of the prior art.
Illustrative examples of the prior art directed to roof ridge ventilators are as follows.
U.S. Pat. No. 5,651,734 discloses a ridge cap roof ventilator applied in roll form comprising a corrugated plastic sheet material.
U.S. Pat. No. 4,676,147 relates to a roof ridge ventilator comprising: a one piece cover member including a pair of flaps and a hinge unitary with the flaps to allow for installing the ventilator on roof ridges of different angles. Vents are located under the flaps. The vents also have an interior baffle structure to deflect air flow and to limit entry of foreign particles through the roof ridge.
U.S. Pat. No. 4,280,399 discloses a roof ventilator comprising a corrugated plastic sheet material which may be mounted transversely across any roof ridge regardless of its contours or roof angles.
U.S. Pat. No. 5,457,920 discloses a ridge top vent for roofs which vent includes grill portions flexibly located longitudinally along the lateral edges. The grill portions have at their distal end a set of flexible teeth adapted to fit on shingles and down between shingles in the gaps therebetween, so as to prevent passages between the grills and the shingles of any debris, insects or vermin.
U.S. Pat. No. 4,817,506 discloses a roof vent which includes a sheet-like cover having an inverted V-shaped cross-section. A pair of baffles are disposed on the lower surface of the cover and include a plurality of spaced partitions for supporting the baffles rigidly against the cover.
U.S. Pat. No. 5,095,810 discloses a roof ridge ventilation system comprising: a ridge vent composed of two panel portions joined together and forming an inverted V-shaped configuration which fits over the peak of the roof. A plurality of V-shaped baffles support the panels. Ventilation ribs are included extending downwardly from each side of the panels to allow passage of air into and out of the openings in the roof. An angled flange is also provided on both sides of the ridge vent to deflect air upwardly and over the roof to create negative air pressure which in turn helps to exhaust stagnant air from the attic space.
U.S. Pat. No. 5,458,538 discloses a roof vent comprising a one-piece plastic body. A plurality of transverse supports are provided for the one-piece plastic body. The system includes a wall to deflect entry of snow and rain. There are also drain openings to allow moisture to escape.
Although the prior art has provided various ventilation systems to address the desiderata, we have found that the balance of the Net Free Open Area for a soffit ventilator and roof ridge ventilator is not always adequately achieved for the reason that the roof ridge ventilators do not allow the passage of sufficient amounts of attic air to pass therethrough while preventing entry of snow, rain, ice and insects.
We believe that the performance of such roof ridge ventilators may be improved by a baffle in which the rows of vent openings run longitudinally along the sides of the roof ridge ventilator panel. In preferred embodiments, the rows of individual slots and slats have a trapezoidal, rectangular or elliptical configuration. Other longitudinal configurations are possible.